GWEN IFILL: Al Gore's endorsement of Howard Dean. After this morning's announcement in New York, Dean and Gore appeared together in Iowa, where voters will cast the first ballots of the campaign six weeks from now. There, the former vice president explained why Dean, and why now.

AL GORE: It's great to be here because today I endorse Howard Dean will be the next president of the United States of America. (Cheers and applause) I have come to the conclusion that among all of the campaigns, Howard Dean and you have managed to do a better job of igniting enthusiasm at the grassroots all across the United States of America, and that's what we need to rebuild the Democratic Party and to rebuild America and to take back the White House and to put our country on the right road again!

GWEN IFILL: Gore said Dean was the only viable candidate who took the correct position in opposing the war in Iraq.

AL GORE: So I looked at this situation and I said, hey, I was in the United States Army in Vietnam. This looks a little bit to me like a quagmire, a potential for a quagmire over there. And so I opposed it and spoke out against it. And I waited and listened. I waited and listened to what all of the candidates in my party had to say and propose about this.

Now I realize it's only one of the issues. But, my friends, this nation has never, in our two centuries and more, made a worse foreign policy mistake than George W. Bush made in putting our troops into that quagmire in Iraq. It was a horrible judgment (cheers and applause) -- misjudgment. And therefore, it is not a minor matter to me that the only major candidate for the nomination of my party that had the good judgment, experience and good sense to feel and see and articulate the right choice, was Howard Dean! ( Cheers and applause ) I think that matters!

GWEN IFILL: Afterwards, Dean talked to reporters about what the endorsement means for his candidacy.

HOWARD DEAN: The truth is we are not going to win this campaign against George Bush unless we united the entire Democratic Party. This is a big step in doing that today.

GWEN IFILL: No other Democratic candidate was as disappointed by Gore's endorsement as was his 2000 running mate, Senator Joe Lieberman of Connecticut. He spoke this morning on "The Today Show."

SEN. JOE LIEBERMAN: What really bothers me is that al is supporting a candidate who is so fundamentally opposed to transformation that bill Clinton brought to the democratic party in 1992. Al Gore will have to explain why he is supporting somebody who I think would take our party and country backwards you will.

GWEN IFILL: Dean then flew to New Hampshire for a Democratic candidates' debate.
-----------------------

KEY QUOTE: this nation has never, in our two centuries and more, made a worse foreign policy mistake than George W. Bush made in putting our troops into that quagmire in Iraq. It was a horrible judgment-- misjudgment.